---

 linux-2.6-npiggin/include/linux/mm_inline.h  |    1 
 linux-2.6-npiggin/include/linux/page-flags.h |    8 +++
 linux-2.6-npiggin/mm/swap.c                  |    2 
 linux-2.6-npiggin/mm/vmscan.c                |   62 ++++++++++++++++-----------
 mm/page_alloc.c                              |    0 
 5 files changed, 49 insertions(+), 24 deletions(-)

diff -puN mm/vmscan.c~vm-page-skipped mm/vmscan.c
--- linux-2.6/mm/vmscan.c~vm-page-skipped	2005-02-09 20:48:24.000000000 +1100
+++ linux-2.6-npiggin/mm/vmscan.c	2005-02-11 20:56:44.000000000 +1100
@@ -361,8 +361,20 @@ static int shrink_list(struct list_head 
 		if (PageWriteback(page))
 			goto keep_locked;
 
-		if (page_referenced(page, 1, sc->priority <= 0))
-			goto activate_locked;
+		if (page_referenced(page, 1, sc->priority <= 0)) {
+			/*
+			 * Has been referenced.  Activate used twice or
+			 * mapped pages, otherwise give it another chance
+			 * on the inactive list
+			 */
+			if (TestSetPageUsedOnce(page) || mapped)
+				goto activate_locked;
+			if (page_test_clear_pte_dirty(page, 1))
+				set_page_dirty(page);
+			if (PageDirty(page))
+				sc->nr_dirty_inactive++;
+			goto keep_locked;
+		}
 
 #ifdef CONFIG_SWAP
 		/*
@@ -581,9 +593,10 @@ static void shrink_cache(struct zone *zo
 			if (TestSetPageLRU(page))
 				BUG();
 			list_del(&page->lru);
-			if (PageActive(page))
+			if (PageActive(page)) {
+				ClearPageUsedOnce(page);
 				add_page_to_active_list(zone, page);
-			else
+			} else
 				add_page_to_inactive_list(zone, page);
 			if (!pagevec_add(&pvec, page)) {
 				spin_unlock_irq(&zone->lru_lock);
@@ -617,7 +630,7 @@ done:
 static void
 refill_inactive_zone(struct zone *zone, struct scan_control *sc)
 {
-	int pgmoved, pgmoved_dirty;
+	int pgmoved;
 	int pgdeactivate = 0;
 	int pgscanned = 0;
 	int nr_pages = sc->nr_to_scan;
@@ -633,7 +646,6 @@ refill_inactive_zone(struct zone *zone, 
 
 	lru_add_drain();
 	pgmoved = 0;
-	pgmoved_dirty = 0;
 
 	spin_lock_irq(&zone->lru_lock);
 	while (pgscanned < nr_pages && !list_empty(&zone->active_list)) {
@@ -717,24 +729,6 @@ refill_inactive_zone(struct zone *zone, 
 		list_add(&page->lru, &l_inactive);
 	}
 
-	/*
-	 * Try to write back as many pages as the number of dirty ones
-	 * we're adding to the inactive list.  This tends to cause slow
-	 * streaming writers to write data to the disk smoothly, at the
-	 * dirtying rate, which is nice.   But that's undesirable in
-	 * laptop mode, where we *want* lumpy writeout.  So in laptop
-	 * mode, write out the whole world.
-	 */
-	zone->nr_dirty_inactive += pgmoved_dirty;
-	pgmoved_dirty = zone->nr_dirty_inactive;
-	if (pgmoved_dirty > zone->nr_inactive / 2
-		|| (!(laptop_mode && !sc->may_writepage)
-			&& pgmoved_dirty > SWAP_CLUSTER_MAX)) {
-		zone->nr_dirty_inactive = 0;
-		wakeup_bdflush(laptop_mode ? 0 : pgmoved_dirty*2);
-		sc->may_writepage = 1;
-	}
-		
 	pagevec_init(&pvec, 1);
 	pgmoved = 0;
 	spin_lock_irq(&zone->lru_lock);
@@ -799,6 +793,7 @@ shrink_zone(struct zone *zone, struct sc
 {
 	unsigned long nr_active;
 	unsigned long nr_inactive;
+	unsigned long count;
 
 	/*
 	 * Add one to `nr_to_scan' just to make sure that the kernel will
@@ -819,6 +814,7 @@ shrink_zone(struct zone *zone, struct sc
 		nr_inactive = 0;
 
 	sc->nr_to_reclaim = SWAP_CLUSTER_MAX;
+	sc->nr_dirty_inactive = 0;
 
 	while (nr_active || nr_inactive) {
 		if (nr_active) {
@@ -837,6 +833,24 @@ shrink_zone(struct zone *zone, struct sc
 				break;
 		}
 	}
+
+	/*
+	 * Try to write back as many pages as the number of dirty ones
+	 * we're adding to the inactive list.  This tends to cause slow
+	 * streaming writers to write data to the disk smoothly, at the
+	 * dirtying rate, which is nice.   But that's undesirable in
+	 * laptop mode, where we *want* lumpy writeout.  So in laptop
+	 * mode, write out the whole world.
+	 */
+	zone->nr_dirty_inactive += sc->nr_dirty_inactive;
+	count = zone->nr_dirty_inactive;
+	if (count > zone->nr_inactive / 2
+		|| (!(laptop_mode && !sc->may_writepage)
+			&& count > SWAP_CLUSTER_MAX)) {
+		zone->nr_dirty_inactive = 0;
+		wakeup_bdflush(laptop_mode ? 0 : count*2);
+		sc->may_writepage = 1;
+	}
 }
 
 /*
diff -puN include/linux/page-flags.h~vm-page-skipped include/linux/page-flags.h
--- linux-2.6/include/linux/page-flags.h~vm-page-skipped	2005-02-09 20:48:24.000000000 +1100
+++ linux-2.6-npiggin/include/linux/page-flags.h	2005-02-11 20:56:43.000000000 +1100
@@ -76,6 +76,8 @@
 #define PG_reclaim		18	/* To be reclaimed asap */
 #define PG_nosave_free		19	/* Free, should not be written */
 
+#define PG_usedonce		20	/* LRU page has been touched once */
+
 
 /*
  * Global page accounting.  One instance per CPU.  Only unsigned longs are
@@ -293,6 +295,12 @@ extern void __mod_page_state(unsigned of
 #define SetPageCompound(page)	set_bit(PG_compound, &(page)->flags)
 #define ClearPageCompound(page)	clear_bit(PG_compound, &(page)->flags)
 
+#define PageUsedOnce(page)	test_bit(PG_usedonce, &(page)->flags)
+#define SetPageUsedOnce(page)	set_bit(PG_usedonce, &(page)->flags)
+#define TestSetPageUsedOnce(page) test_and_set_bit(PG_usedonce, &(page)->flags)
+#define ClearPageUsedOnce(page)	clear_bit(PG_usedonce, &(page)->flags)
+#define TestClearPageUsedOnce(page) test_and_clear_bit(PG_usedonce, &(page)->flags)
+
 #ifdef CONFIG_SWAP
 #define PageSwapCache(page)	test_bit(PG_swapcache, &(page)->flags)
 #define SetPageSwapCache(page)	set_bit(PG_swapcache, &(page)->flags)
diff -puN mm/truncate.c~vm-page-skipped mm/truncate.c
diff -puN mm/swap.c~vm-page-skipped mm/swap.c
--- linux-2.6/mm/swap.c~vm-page-skipped	2005-02-09 20:48:24.000000000 +1100
+++ linux-2.6-npiggin/mm/swap.c	2005-02-11 20:56:43.000000000 +1100
@@ -267,6 +267,7 @@ void __pagevec_lru_add(struct pagevec *p
 		}
 		if (TestSetPageLRU(page))
 			BUG();
+		ClearPageUsedOnce(page);
 		add_page_to_inactive_list(zone, page);
 	}
 	if (zone)
@@ -296,6 +297,7 @@ void __pagevec_lru_add_active(struct pag
 			BUG();
 		if (TestSetPageActive(page))
 			BUG();
+		ClearPageUsedOnce(page);
 		add_page_to_active_list(zone, page);
 	}
 	if (zone)
diff -puN include/linux/swap.h~vm-page-skipped include/linux/swap.h
diff -puN include/linux/mm_inline.h~vm-page-skipped include/linux/mm_inline.h
--- linux-2.6/include/linux/mm_inline.h~vm-page-skipped	2005-02-09 20:48:24.000000000 +1100
+++ linux-2.6-npiggin/include/linux/mm_inline.h	2005-02-11 20:56:43.000000000 +1100
@@ -35,6 +35,7 @@ del_page_from_lru(struct zone *zone, str
 		ClearPageActive(page);
 		zone->nr_active--;
 	} else {
+		ClearPageUsedOnce(page);
 		zone->nr_inactive--;
 	}
 }
diff -puN mm/page_alloc.c~vm-page-skipped mm/page_alloc.c

_